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-rw-r--r--helix-dap/src/transport.rs279
1 files changed, 279 insertions, 0 deletions
diff --git a/helix-dap/src/transport.rs b/helix-dap/src/transport.rs
new file mode 100644
index 00000000..3f4eec43
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+++ b/helix-dap/src/transport.rs
@@ -0,0 +1,279 @@
+use crate::{Error, Event, Result};
+use anyhow::Context;
+use log::{error, info, warn};
+use serde::{Deserialize, Serialize};
+use serde_json::Value;
+use std::collections::HashMap;
+use std::sync::Arc;
+use tokio::{
+ io::{AsyncBufRead, AsyncBufReadExt, AsyncReadExt, AsyncWrite, AsyncWriteExt},
+ sync::{
+ mpsc::{unbounded_channel, Sender, UnboundedReceiver, UnboundedSender},
+ Mutex,
+ },
+};
+
+#[derive(Debug, Clone, Deserialize, Serialize)]
+pub struct Request {
+ #[serde(skip)]
+ pub back_ch: Option<Sender<Result<Response>>>,
+ pub seq: u64,
+ pub command: String,
+ pub arguments: Option<Value>,
+}
+
+#[derive(Debug, PartialEq, Clone, Deserialize, Serialize)]
+pub struct Response {
+ // seq is omitted as unused and is not sent by some implementations
+ pub request_seq: u64,
+ pub success: bool,
+ pub command: String,
+ pub message: Option<String>,
+ pub body: Option<Value>,
+}
+
+#[derive(Debug, Clone, Deserialize, Serialize)]
+#[serde(tag = "type", rename_all = "camelCase")]
+pub enum Payload {
+ // type = "event"
+ Event(Event),
+ // type = "response"
+ Response(Response),
+ // type = "request"
+ Request(Request),
+}
+
+#[derive(Debug)]
+pub struct Transport {
+ id: usize,
+ pending_requests: Mutex<HashMap<u64, Sender<Result<Response>>>>,
+}
+
+impl Transport {
+ pub fn start(
+ server_stdout: Box<dyn AsyncBufRead + Unpin + Send>,
+ server_stdin: Box<dyn AsyncWrite + Unpin + Send>,
+ server_stderr: Option<Box<dyn AsyncBufRead + Unpin + Send>>,
+ id: usize,
+ ) -> (UnboundedReceiver<Payload>, UnboundedSender<Request>) {
+ let (client_tx, rx) = unbounded_channel();
+ let (tx, client_rx) = unbounded_channel();
+
+ let transport = Self {
+ id,
+ pending_requests: Mutex::new(HashMap::default()),
+ };
+
+ let transport = Arc::new(transport);
+
+ tokio::spawn(Self::recv(transport.clone(), server_stdout, client_tx));
+ tokio::spawn(Self::send(transport, server_stdin, client_rx));
+ if let Some(stderr) = server_stderr {
+ tokio::spawn(Self::err(stderr));
+ }
+
+ (rx, tx)
+ }
+
+ async fn recv_server_message(
+ reader: &mut Box<dyn AsyncBufRead + Unpin + Send>,
+ buffer: &mut String,
+ ) -> Result<Payload> {
+ let mut content_length = None;
+ loop {
+ buffer.truncate(0);
+ if reader.read_line(buffer).await? == 0 {
+ return Err(Error::StreamClosed);
+ };
+
+ if buffer == "\r\n" {
+ // look for an empty CRLF line
+ break;
+ }
+
+ let header = buffer.trim();
+ let parts = header.split_once(": ");
+
+ match parts {
+ Some(("Content-Length", value)) => {
+ content_length = Some(value.parse().context("invalid content length")?);
+ }
+ Some((_, _)) => {}
+ None => {
+ // Workaround: Some non-conformant language servers will output logging and other garbage
+ // into the same stream as JSON-RPC messages. This can also happen from shell scripts that spawn
+ // the server. Skip such lines and log a warning.
+
+ // warn!("Failed to parse header: {:?}", header);
+ }
+ }
+ }
+
+ let content_length = content_length.context("missing content length")?;
+
+ //TODO: reuse vector
+ let mut content = vec![0; content_length];
+ reader.read_exact(&mut content).await?;
+ let msg = std::str::from_utf8(&content).context("invalid utf8 from server")?;
+
+ info!("<- DAP {}", msg);
+
+ // try parsing as output (server response) or call (server request)
+ let output: serde_json::Result<Payload> = serde_json::from_str(msg);
+
+ Ok(output?)
+ }
+
+ async fn recv_server_error(
+ err: &mut (impl AsyncBufRead + Unpin + Send),
+ buffer: &mut String,
+ ) -> Result<()> {
+ buffer.truncate(0);
+ if err.read_line(buffer).await? == 0 {
+ return Err(Error::StreamClosed);
+ };
+ error!("err <- {}", buffer);
+
+ Ok(())
+ }
+
+ async fn send_payload_to_server(
+ &self,
+ server_stdin: &mut Box<dyn AsyncWrite + Unpin + Send>,
+ mut req: Request,
+ ) -> Result<()> {
+ let back_ch = req.back_ch.take();
+ let seq = req.seq;
+ let json = serde_json::to_string(&Payload::Request(req))?;
+ if let Some(back) = back_ch {
+ self.pending_requests.lock().await.insert(seq, back);
+ }
+ self.send_string_to_server(server_stdin, json).await
+ }
+
+ async fn send_string_to_server(
+ &self,
+ server_stdin: &mut Box<dyn AsyncWrite + Unpin + Send>,
+ request: String,
+ ) -> Result<()> {
+ info!("-> DAP {}", request);
+
+ // send the headers
+ server_stdin
+ .write_all(format!("Content-Length: {}\r\n\r\n", request.len()).as_bytes())
+ .await?;
+
+ // send the body
+ server_stdin.write_all(request.as_bytes()).await?;
+
+ server_stdin.flush().await?;
+
+ Ok(())
+ }
+
+ fn process_response(res: Response) -> Result<Response> {
+ if res.success {
+ info!("<- DAP success in response to {}", res.request_seq);
+
+ Ok(res)
+ } else {
+ error!(
+ "<- DAP error {:?} ({:?}) for command #{} {}",
+ res.message, res.body, res.request_seq, res.command
+ );
+
+ Err(Error::Other(anyhow::format_err!("{:?}", res.body)))
+ }
+ }
+
+ async fn process_server_message(
+ &self,
+ client_tx: &UnboundedSender<Payload>,
+ msg: Payload,
+ ) -> Result<()> {
+ match msg {
+ Payload::Response(res) => {
+ let request_seq = res.request_seq;
+ let tx = self.pending_requests.lock().await.remove(&request_seq);
+
+ match tx {
+ Some(tx) => match tx.send(Self::process_response(res)).await {
+ Ok(_) => (),
+ Err(_) => error!(
+ "Tried sending response into a closed channel (id={:?}), original request likely timed out",
+ request_seq
+ ),
+ }
+ None => {
+ warn!("Response to nonexistent request #{}", res.request_seq);
+ client_tx.send(Payload::Response(res)).expect("Failed to send");
+ }
+ }
+
+ Ok(())
+ }
+ Payload::Request(Request {
+ ref command,
+ ref seq,
+ ..
+ }) => {
+ info!("<- DAP request {} #{}", command, seq);
+ client_tx.send(msg).expect("Failed to send");
+ Ok(())
+ }
+ Payload::Event(ref event) => {
+ info!("<- DAP event {:?}", event);
+ client_tx.send(msg).expect("Failed to send");
+ Ok(())
+ }
+ }
+ }
+
+ async fn recv(
+ transport: Arc<Self>,
+ mut server_stdout: Box<dyn AsyncBufRead + Unpin + Send>,
+ client_tx: UnboundedSender<Payload>,
+ ) {
+ let mut recv_buffer = String::new();
+ loop {
+ match Self::recv_server_message(&mut server_stdout, &mut recv_buffer).await {
+ Ok(msg) => {
+ transport
+ .process_server_message(&client_tx, msg)
+ .await
+ .unwrap();
+ }
+ Err(err) => {
+ error!("err: <- {:?}", err);
+ break;
+ }
+ }
+ }
+ }
+
+ async fn send(
+ transport: Arc<Self>,
+ mut server_stdin: Box<dyn AsyncWrite + Unpin + Send>,
+ mut client_rx: UnboundedReceiver<Request>,
+ ) {
+ while let Some(req) = client_rx.recv().await {
+ transport
+ .send_payload_to_server(&mut server_stdin, req)
+ .await
+ .unwrap()
+ }
+ }
+
+ async fn err(mut server_stderr: Box<dyn AsyncBufRead + Unpin + Send>) {
+ let mut recv_buffer = String::new();
+ loop {
+ match Self::recv_server_error(&mut server_stderr, &mut recv_buffer).await {
+ Ok(_) => {}
+ Err(err) => {
+ error!("err: <- {:?}", err);
+ break;
+ }
+ }
+ }
+ }
+}